8 Ball of Breaking Out of Block
Give yourself room to play so that you can free up your mind.
Search for excitement and stuff that is fun. Don't think of it as writing but more like simply experiencing and taking notes.
Don't forget to read. If you want to be good writer, be a good reader. You want to be a funny writer, read funny and twisted stuff.
Make something or write something just for the fun of doing it...no parimeters or barriers. There is no right or wrong way to create. The only wrong is to not do it.
When ideas aren't flowing it's a good time to rewrite.
Take the jokes you do have and play with them. Put different punches to them, change the situations, tag etc.
Don't tie so much self worth to artistic success. Creating art is one thing, being successful with it is a different animal all together. First enjoy the fun of making fun, become successful at that.
Get a hold of the idea that struggles are solutions trying to break out. Work with them....or should I say PLAY with them.
The closer you get to becoming childlike in your approach to comedy the more likely you are to free yourself of overthinking.